Commercial aircraft are favorite targets of hijackers. It is desirable to prevent hijackers from taking unauthorized control of aircraft, as such hijacking activities compromise public safety. Due to the nature of aircraft operation, the pilots need immediate access to the controls at all times during the flight in order to insure and provide for a safe flight. The use of locks or keys can put access to the controls in jeopardy while flying. The use of persistent access codes, such as a password keyed to each individual pilot causes administrative problems for the airline. This is because pilots and crew change aircraft constantly, and often with little advance notice. Tight schedules preclude easy transfer of access codes from one aircraft to another. Storing large numbers of access codes on board each aircraft presents security risks. Furthermore, access codes and passwords must be updated constantly in order to provide good security, causing an additional administrative burden. Thus a better technique is required.
Embodiments of this invention provide systems whereby vehicles such as commercial aircraft may be effectively protected from unauthorized operating by hijackers or terrorists, without undue administrative burden on the part of the airline or crew. Furthermore, it is practical and cost effective. In an aspect of an embodiment of the invention, a non-persistent identifier is used to establish the identity of authorized personnel. Subsequently, when an unusual event is detected, or at certain specified points during the vehicle trip, the authorized personnel's identity is confirmed by re-entry of the non-persistent identifier, as a confirmation identifier, before the vehicle is allowed to continue with normal operations. When the trip is completed, the non-persistent identifiers are deleted.